1. Field of the Invention
The present invention relates to a tool storage device mounted on a machining center or tool machine having an automatic tool exchange mechanism.
2. Description of Related Art
A conventional tool storage device mounted on a machining center or machine tool which transfers a tool pot to a specified dividing position along a specified path and turns the tool pot thus transferred to the specified dividing position to a tool storage state or to a tool exchange state.
Japanese Utility Model Publication No. 4-2756 discloses, for example, a device which grips a part projected from the back side of a tool pot by claws of a movable mechanism by moving up or down the movable mechanism. In this tool storage device, a rotatable roller is disposed at the part projected from the back side of the tool pot. Since a strong friction force is not applied between the tool pot and the movable mechanism, the frictional wear between the roller and the movable mechanism can be reduced and the tool pot can be turned smoothly in response to the up-and-down movement of the movable mechanism. However, in the tool storage device having the roller at the part gripped by the movable mechanism, since each tool pot is required to have the roller and a support shaft therefor separately from a turning shaft disposed at the center of the turning of the tool pot, the tool pot and hence the whole tool storage device tend to necessitate high manufacturing cost.
Further, in the conventional tool storage device, the movable mechanism uses a driving source such as an air cylinder or a hydraulic cylinder as a turning mechanism for turning the tool pot to the tool storage state or to the tool exchange state. In this arrangement, when an air supply to the air cylinder from an air source is stopped to stop a machine operation in a factory, pressure for keeping the piston in the air cylinder at one dead center is not applied to the piston and only the self weight of the tool pot or the self weight of the other movable parts is applied to the piston. This sometimes results in turning the tool pot which is to be kept essentially in the tool storage state to the tool exchange state, or in turning the tool pot which is to be kept essentially in the tool exchange state to the tool storage state. When the machine operation is to be restarted in the factory, the tool pot is possibly held turned to undesired state erroneously. This erroneous condition is required to be removed before the tool machine is restarted. Further, when the air supply to the air cylinder is restarted, the piston in the air cylinder might be returned suddenly to an original position. Thus, it becomes also necessary to take some safety measures so that an operator should not touch the piston carelessly.
Still further, in the conventional tool storage device, in order to restrict the tool pot from dropping from a transfer mechanism during the transfer, for example, a bearing hole is provide in the tool pot and in the parts of the transfer mechanism, respectively, and a turning shaft is inserted through the bearing hole and is mounted such that the turning shaft does not slip off to thereby considerably firmly join the tool pot to the parts. In this case, joining the tool pots to the transfer mechanism requires considerable labor and time. In particular, when the tool pots are mounted on the transfer mechanism after the transfer mechanism is mounted in the tool storage device, a manual work in a narrow limited space is required. On the other hand, when tool pots are mounted to the parts of the transfer mechanism to be attached together to the transfer mechanism, it is necessary to mount the parts of the transfer mechanism whose weight is increased by many tool pots. In either case, the mounting or dismounting the tool pots for an assembling work or maintenance is extremely troublesome.